Which statement best describes Korsakoff syndrome?

• A. A chronic memory disorder often following Wernicke encephalopathy
• B. An acute, reversible delirium due to alcohol
• C. A motor disorder with preserved memory
• D. Caused by vitamin B12 deficiency

Answer: (A)

Korsakoff syndrome is a chronic amnestic condition caused by thiamine (vitamin B1) deficiency, most often after an episode of Wernicke encephalopathy in people with long-term alcohol misuse. The hallmark is severe trouble forming new memories (anterograde amnesia), with retrograde memory gaps and often confabulation to fill in missing memories; other thinking skills may be relatively preserved, at least early on. Because it typically follows an acute thiamine-deficiency event, it is described as a long-lasting memory disorder that can persist after the immediate illness has passed.

This fits the statement best because Korsakoff syndrome is defined by its persistent memory impairment that commonly occurs after Wernicke encephalopathy. It is not an acute, reversible delirium like delirium tremens, nor a motor disorder with preserved memory, and it is due to thiamine deficiency rather than vitamin B12 deficiency.